This application is a 35 U.S.C. § 371 National Stage Application of PCT/EP2012/061638, filed on Jun. 19, 2012, which claims the benefit of priority to Serial No. DE 10 2011 080 971.6, filed on Aug. 16, 2011 in Germany, the disclosures of which are incorporated herein by reference in their entirety.
The disclosure relates to a sensor, especially for acceleration measurement or rotation rate measurement according to the type described below, as well as to a corresponding sensor unit according to the type described below, and to a corresponding method for manufacturing a sensor unit according to the type described below.
Sensors with at least one sensor element for measuring inertial variables, such as e.g. the acceleration and/or the rotation rate, are usually installed in modern safety systems. The acceleration and/or rotation rate sensors comprise oscillating masses that are operated in a specified frequency range. If noise variables or interference frequencies occur that lie in the specified frequency range and do not originate from the variable to be measured, such as e.g. oscillations of the drive, then the measurement function of the sensor can be adversely affected or completely disrupted. In many application cases in which a high signal quality is necessary and/or in which there is at least one noise source or interference frequency at the installation position, interruption of the chain of action of the interference is necessary. The chain of action of the interference can especially be interrupted at the circuit board on which the sensor with the sensor element is disposed.
In the published patent application DE 10 2009 001 930 A1 e.g. a sensor unit with a housing and a circuit board disposed within the housing, on which a sensor with a sensor element is disposed, are described. An elastomeric element, which connects the circuit board electrically and mechanically to the housing, is attached between the circuit board and the housing. Mechanical decoupling of the sensor element from the housing is achieved by the elastomeric element. Interference in the form of interference oscillations or interference frequencies, which can act on the housing, is damped by the elastomeric element. Furthermore, additional means for electrically contacting the circuit board can be saved as a result of the conducting elastomeric element.
In the published patent application DE 10 2009 000 571 A1, e.g. a sensor unit with a housing and a circuit board, on which a sensor with a sensor element is disposed and which is disposed in the housing, are described. The circuit board is implemented in a flexible form. Mechanical decoupling of the sensor element from the housing is achieved by the flexible circuit board. Interference frequencies that act upon the housing are damped by the flexible circuit board.